Abstract:  The FE（finite element） modeling method of UNJ threaded hi-lock nuts was investigated, and a modeling program was written to generate structured meshes, through which the fine FE meshed model was established. The extrusion process, assembly process and loosening behavior under transverse loads of hi-lock nuts were simulated by finite element method（FEM）, and the simulated locking torque was verified by tightening tests. The simulation results show that within a certain range, the maximum radial displacement and the locking torque of the hi-lock nuts are linearly related to the extrusion amount approximately. With the extrusion amount increases, the maximum radial displacement and the locking torque both increase. The higher the locking torque of the hi-lock nuts, the better the anti-loosening performance. However, there is an optimal value of the extrusion amount for the anti-loosening performance. Once the extrusion amount exceeds the optimum value, increasing the amount of extrusion does not have a significant effect on the improvement of the anti-loosening performance.

Key words:  hi-lock nut, extrusion, locking torque, anti-loosening performance

摘要： 针对UNJ螺纹高锁螺母开展了有限元建模方法研究，编写了可生成结构化网格的建模程序，并建立了精细的有限元网格模型。对高锁螺母的收口过程、装配过程及受到横向载荷下的松动行为进行了有限元仿真，并通过拧紧试验对仿真得到的锁紧力矩值进行了验证。仿真结果表明：在一定收口量范围内，高锁螺母的最大径向位移量以及锁紧力矩均与收口量近似满足线性关系，且随着收口量的增大，最大径向位移量与锁紧力矩均增大；高锁螺母的锁紧力矩越大对应防松性能越好，然而收口量对防松性能存在最优值，当收口量超过最优值后，继续增大收口量对防松性能的提升效果并不显著。

关键词: 高锁螺母, 收口, 锁紧力矩, 防松性能